1 files changed, 5 insertions, 0 deletions
diff --git a/src/mac/hmac/hmac.h b/src/mac/hmac/hmac.h
index 33af62f6a..505d0dd6b 100644
--- a/src/mac/hmac/hmac.h
+++ b/src/mac/hmac/hmac.h
@@ -23,6 +23,11 @@ class BOTAN_DLL HMAC : public MessageAuthenticationCode
       std::string name() const;
       MessageAuthenticationCode* clone() const;
 
+      Key_Length_Specification key_spec() const
+         {
+         return Key_Length_Specification(0, 2*hash->hash_block_size());
+         }
+
       /**
       * @param hash the hash to use for HMACing
       */